Conventionally, dedicated hardware is used for a communication device such as a router or a gateway. In recent years, a technology to virtualize functions relating to network services of various communication devices (hereinafter referred to as network service functions) as software on a general-purpose server (network functions virtualization (NFV)) has been put into practical use.
As a related technology, a technology has been proposed in which a cloud controller migrates a virtual machine (VM) into a base that has the largest number of communication sessions to the VM (see, for example, Patent Document 1).
A technology has also been proposed that includes means for selecting a transfer destination of a packet that will be transferred to a plurality of routes in order to establish a communication session with a communication function from among a plurality of virtual machines, and means for transferring the packet to the selected virtual machine (see, for example, Patent Document 2).
Further, a technology has been proposed for managing a wide area network (WAN) and an NW function cloud as separate networks and linking network control between the WAN and the NW function cloud (see, for example, Patent Document 3).
Furthermore, a technology has been proposed for measuring a network delay by referencing flow information stored in a flow information database and calculating a difference between the time when a packet was transmitted via a port of a transfer device and the time when a response packet to the packet was received (see, for example, Patent Document 4).
[Patent Document 1] Japanese Laid-open Patent Publication No. 2015-41198
[Patent Document 2] International Publication Pamphlet No. 2014-208538
[Patent Document 3] Japanese Laid-open Patent Publication No. 2015-43528
[Patent Document 4] Japanese Laid-open Patent Publication No. 2013-240017